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Your pregnancy and baby guide

Severe vomiting in pregnancy

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Sickness in pregnancy (sometimes called morning sickness) is common. Around 8 out of every 10 pregnant women feel sick (nausea), are sick (vomiting) or both during pregnancy. This does not just happen in the morning.


Some pregnant women experience very bad nausea and vomiting. They might be sick many times a day and be unable to keep food or drink down, which can impact on their daily life.


Exactly how many pregnant women get HG is not known as some cases may go unreported, but it's thought to be around 1 to 3 in every 100.

If you are being sick frequently and cannot keep food down, tell your midwife or doctor, or contact the hospital as soon as possible. There is a risk you may become dehydrated, and your midwife or doctor can make sure you get the right treatment.

Symptoms of hyperemesis gravidarum


Signs and symptoms of HG include:

  • prolonged and severe nausea and vomiting
  • weight loss
  • low blood pressure (hypotension) when standing



There are other conditions that can cause nausea and vomiting, and your doctor will need to rule these out first.

See the website for videos and written interviews of women talking about their experiences of hyperemesis gravidarum and how they coped.

What causes hyperemesis gravidarum?




Treating hyperemesis gravidarum







Will hyperemesis gravidarum harm my baby?

HG can make you feel very unwell, but it's unlikely to harm your baby if treated effectively.

However, if it causes you to lose weight during pregnancy, there is an increased risk that your baby may be born smaller than expected (have a low birthweight).

Other symptoms you may experience


  • extremely heightened sense of smell
  • excessive saliva production
  • headaches and constipation from dehydration

If you experience these symptoms, you are not alone. Many women have them and they will go away when the HG stops or the baby is born.

How you might feel

The nausea and vomiting of HG can impact your life at a time when you were expecting to be enjoying pregnancy and looking forward to the birth of your baby.

It can affect you both emotionally and physically. The symptoms can be hard to cope with. Without treatment HG may also lead to further health complications, such as depression or tears in your oesophagus.



  • isolated because you do not know anyone who understands what it's like to have HG
  • confused as to why this is happening to you
  • unsure about how to cope with the rest of the pregnancy if you continue to feel very ill

If you feel any of these, do not keep it to yourself. Talk to your midwife or doctor, and explain the impact HG is having on your life and how it is making you feel. You could also talk to your partner, family and friends if you want to.

If you want to talk to someone who has been through HG, you can contact Pregnancy Sickness Support's help section. They have a support network across the UK and can put you in touch with someone who has had HG.

Bear in mind that HG is much worse than regular pregnancy sickness. It is not the result of anything you have or have not done, and you do need treatment and support.

Another pregnancy

If you have had HG before, it's likely you will get it again in another pregnancy.

If you decide on another pregnancy, it can help to plan ahead, such as arranging child care so you can get plenty of rest.

You could try doing things that helped last time.

Talk to your doctor about starting medicine early.

Blood clots and hyperemesis gravidarum

Because HG can cause dehydration, there's also an increased risk of having a blood clot (deep vein thrombosis), although this is rare. 

If you are dehydrated and immobile, there is treatment that you can be given to prevent blood clots.

Read more about how to prevent deep vein thrombosis.

Page last reviewed: 04/10/2019
Next review due: 04/10/2022